Voice over IP chat software allows people to make phone calls over the Internet by converting analog audio signals into digital data packets. Because of the way the packets are sent over the Web, sometimes by a “peer-to-peer” connection, it can be complex and costly for law enforcement agencies to listen in on them. This has previously led some countries, like Ethiopia and Oman, to block VoIP services on “security” grounds.

Now, with this new technology, suspects whom authorities wanted to monitor could be identified through their username and subscriber data, or by billing records that associate names and addresses with usernames, making not only calls but “any other data streams such as pure data and/or video or multimedia data” available for interception.

Microsoft has filed a similar patent for “legal intercept” technology designed to be used with VoIP services like Skype to “silently copy communication transmitted via the communication session.”